In the operation of paper machines, which continuously produce a paper web of great width, travelling at speeds in the range of about 2000 to 4000 feet per minute, the economic operation of the process is dependent on successfully reeling newly formed pressed and dried paper web onto reel bars to provide large paper rolls. These rolls are thereafter removed from the paper making machine for further processing into paper product.
Successful reeling or winding is frequently effected in modern paper machines by using an auto loader such as disclosed in Applicant's U.S. Pat. No. 4,744,720 issued May 17, 1988. The auto loader contains empty reel bars in stored relation above the reeling station. The reel is lowered downwardly when required into a location above the travelling paper web to receive and take up the severed end of the web. The web is turned up towards the spinning reel bar as the preceding formed paper roll is severed and removed.
Such operations involve displacement of an empty reel bar into an initial reeling position with respective end bearings of the reel bar secured within a bearing end clamp arrangement. Upon severance of the moving paper web from a previously formed roll located in a second reeling position spaced from the initial reeling position of a new reel bar, the new rotating reel bar, running in contacting relation with the reel driving drum contacts the released web, and turn-up of the web free end occurs. That is to say, the free end of the severed web makes adhering contact with the surface of the new reel bar and a new roll commences formation.
If web turn-up is achieved successfully, the reel bar bearing end clamps may be released, permitting a reel handling mechanism to move the partially loaded reel bar to the second, reel locating station, for completion of roll formation.
It is the detection of completed web turn-up to which the present invention is directed.
The reliable detection of changes in reel bar position is complicated by machine vibration and possible bouncing of the reel bar, which may occur when there is a rough turn-up, so that roll formation does not proceed smoothly.
In one prior paper web handling arrangement mechanical feelers have been used in an effort to track the axial location of reel bar bearings. An example of such use may be found in U.S. Pat. No. 4,358,066 issued Nov. 9, 1982 to Deutschle et al. The use of light in a position sensing mechanism is shown in U.S. Pat. No. 4,762,292 issued Aug. 9, 1988 to D'Anci, in relation to a narrow recording tape, using reflective beads. Light sensors also are used in controlling a paper reeling operation, as shown in U.S. Pat. No. 4,267,752 issued May 19, 1981 to Byrt et al wherein sensor signals are used to control reeling tension.
U.S. Pat. No. 4,131,206 issued Dec. 26, 1978 to Kawada et al although directed to the printing industry is of interest, in that it relates to the large mass of wound paper rolls, operating at like speeds to that of a paper machine, and demonstrates the criticality of correct timing in their handling.